Insulated containers have become popular for carrying either articles that may best be served cool, such as beverages or salads, or warm, such as appetizers, hot dogs, and so on. Such containers are frequently used to carry liquids, whether hot liquids, such as soup containers, coffee or tea, or cold liquids such as beer, soft drinks, or other carbonated beverages, juices and milk. Sometimes these containers may by used to carry lunches, which may include a sandwich, fruit, carrot and celery sticks, a drink, cookies, and so on.
Portable insulated containers tend to be of two types: hard-sided insulated containers or soft-sided insulated containers. Hard-sided portable insulated containers tend to be made of moulded plastic, with an inner layer, or wall, and an outer layer or wall, with an insulation space (which may be an air-space) therebetween. Hard-sided portable insulated containers are, as might be understood by the name, substantially rigid. The adjective “portable” is sometimes generous, as a full cooler capable of carrying 24 cans at 385 mL each, plus ice, may have significant weight. Hard-sided coolers, by their nature, may tend to be bulky, and, even when provided with a handle on top or handles at the ends may tend not to be particularly convenient to carry. A user's perception of the convenience of their portability may diminish with each additional step.
A soft-sided cooler, by contrast, relies on external insulated wall structure that is not substantially rigid. In some instances the external insulated wall structure may be foldable between collapsed and expanded conditions. The insulated wall structure may typically include an outside layer of webbing or fabric, an inside layer of webbing or fabric, and a layer of flexible insulation positioned between the inner and outer layers. Soft-sided coolers may sometimes include substantially rigid liners to assist in permitting the cooler to maintain a given shape, or to protect items inside the cooler from being crushed.